I installed a 1.44MB FDD (for use with DD media, of course) in some late XT clone, one with that highly-integrated Faraday chipset.
It would be reasonable to assume that such a late clone has a BIOS with all the features of IBM's 01/10/86.

But there's a problem: by default DOS treats that FDD as a 360KB one, attempts to format a 720KB diskette (format /f:720) result with "Parameters not compatible..." error.
DRIVPARM solves the problem.

Does it mean that my BIOS lacks support for 720KB drives?
IBM 5160 with a late BIOS doesn't need DRIVPARM here, does it?

A few questions -
1st, the floppy drive is iffy. Only reads disks 1/2 the time, if that. I'm reading that bad caps are a common problem, and I'm going to guess that's my issue, but input is appreciated before I go trying to find parts.

2nd, there is no hard drive installed, but I see a ~40 pin header on the motherboard, I'm guessing is for a hard drive. What hard drives are compatible? Is it a standard 40 pin "IDE" cable, or do I need a special cable for it? Should I just go XT-IDE with CF?

3rd, What's the big 1/4" phono style jack on the back for?

Lastly, while the color screen is beautiful, and all the colors seem to show fine with the system test disk, the white text in DOS & Basic seems a bit 'purplish', any ideas if there's an adjustment?
]]>PCs and Cloneszombienerdhttp://www.vcfed.org/forum/showthread.php?59199-PS2-Model-25-004-QuestionsXT-IDE rev 4 Developmenthttp://www.vcfed.org/forum/showthread.php?59185-XT-IDE-rev-4-Development&goto=newpost
Tue, 15 Aug 2017 18:01:03 GMTI've been working on revision 4 of the Hargle/N8VEM open source XT-IDE design. It started off with the following changes, mostly suggested by users here and on IRC:

I also added better test points with labels on both the front and the back to make the Slot 8 Support mod board easier to install, and routed *CARDSEL through the last DIP position on the I/O address switches. The status LED got flipped so that I can use some right-angle LEDs I've got in stock on personal builds, too.

During the process, I ran into Alan Hightower (eeguru) at VCF East, who is working on the NetPi-IDE Raspberry Pi interface. He'd ran into a timing problem with how the high byte is latched on the XT-IDE and had to work around it with his FPGA design. He described the problem to me, which seemed to be a race condition on the read side of things: when *IOR de-asserted from the ISA bus, a sufficiently fast ATA device, like his NetPi-IDE board, would present invalid data to the high byte latch before it could de-assert and latch the data. This is due to the propagation delay in the logic on the original Hargle/N8VEM design, which I think is worth keeping as it preserves BIOS compatibility with the older BIOSes. The solution is to slow down the *IOR signal a little. I hooked up the HP 1650A logic analyzer to take a look:

IORISA is the *IOR strobe essentially directly off of the ISA bus. IORIDE is the same signal after passing through four sections of a 74LS04 inverter, this adds around 20 nS of gate delay. HI RD is the latch strobe to U1, the high byte read latch that stores the upper 8 bits of the ATA device's output data during a read, so we can grab it later. As seen in the timing diagram, where HI RD used to lag IORISA by 10 nS, it now leads by 10 nS due to the 20 nS delay chain. This means the latch stores its value 10 nS before the ATA device stops outputting valid data, which is well within the spec for even the 74LS573 latch (the kits typically come with 74F573 latches, because I have a supply of them).

I decided to go ahead and check out the write timing as well, though it hadn't been pointed out as a problem:

IOWIDE is the *IOW signal essentially directly off of the ISA bus. HI WR is the latch strobe for storing the upper byte before doing a 16-bit write to the ATA device. HI OUT is the delayed "2 signal" from the XT-IDE logic (I've since relabeled it *HI_BYTE_OUT on the schematic, which I think is clearer). It was delayed by running it through two sections of a 74LS04 inverter and one section of a 74LS32 OR gate, with one input of the OR gate tied to ground. As seen in the timing diagram, *HI_BYTE_OUT now de-asserts 10 nS after the *IOW line, ensuring that data is presented to the ATA device for 10 nS past the end of the ATA write operation. I'm not sure if many (or any) ATA devices are this picky about the timing, but correcting it at the same time as making other rev 4 changes didn't require any spare gates.

All of this was breadboarded on an old XT-IDE rev 3 prototype board from the initial rev 3 design, with a 74LS04 dead-bugged onto the circuit board and wired in. I made the read delay chain modifications and had some more prototypes run. Alan has one of them, which he used to confirm that the read timing was fixed. I modified a second with a socket for the 74LS04 so that I could test faster devices, as well as adding in the high byte output delay. I tested 74S04, 74LS04, 7404, and 74F04 devices, to make sure that whatever got stuck in there by someone assembling an XT-IDE would provide sufficient delay. All provided sufficient delay, the 7404 was the only measurable difference, providing around 25 nS instead of 20 nS, which is fine.

I've ordered production boards for the XT-IDE rev 4, since I'm almost out of XT-IDE rev 3 boards from the last run. They'll look approximately like this:

Those are from the earlier prototype order, since then I've switched the OSHW logo to a copper/solder mask relief, and moved the identification text back toward the OSHW logo. There have been some routing tweaks as well, but nothing major, other than adding in the hi byte output delay. Probably the biggest change people will notice is the extra 74LS04, and the switch to custom IC silkscreen legends from the stupid defaults included in newer KiCad releases. I'd stuck with the older KiCad 2.x style IC silkscreens on the rev 3 board because I thought the pin 1 designations were really, truly awful on KiCad 4.x default libraries.
]]>PCs and Clonesglitchhttp://www.vcfed.org/forum/showthread.php?59185-XT-IDE-rev-4-Developmenthttp://www.vcfed.org/forum/showthread.php?59169-IBM-6901-quot-Personal-Typing-System-quot&goto=newpost
Mon, 14 Aug 2017 02:24:27 GMTI saw this on a shelf when I was doing side shopping on my vacation, minus the keyboard, monitor and printer.
Image:...I saw this on a shelf when I was doing side shopping on my vacation, minus the keyboard, monitor and printer.

Spec wise it is identical to the PS/2 model 30 because inside the case turned 90 degrees is a model 30 planar. The expansion cabinet contains the 72X6757 External floppy adapter and two unused ISA slots. A quick googling seems to indicate it will work with those IBM 4869 external 360k 5.25" floppy drives that everyone seems to have at least one of but never the interface card.
The CMOS battery is a Panasonic BR-2/3A lithium cell. I have spares.

The first time I turned it on it complained about the date and time and then tried to boot off the hard drive which is one of those blasted IBM proprietary ones. It sounds fantastic with no nasty fluttering or whining noises however it gave itself a few attempts and then hung at a blinking cursor. When rebooted while the drive did its seek test it gave a 1701 error. Awesome. I don't have any more of the narrow edge connector drives. I gave my last one away last year because I didn't expect to ever need it.
I grabbed the Starter diskette and Advanced diagnostics diskette for the model 30 from here and ran through everything once I replaced the battery. One thing I noticed is that it keeps trying to handle the external floppy as if it is a 720kb drive so it never works properly. The other is that I can get the hard drive to respond to some of the tests but they still all fail with "UNDETERMINED ERROR". I know with the later wide edge connector drives there's a few SMD caps that you need to replace but on these older drive they are miniature radials. The machine and the drive seem so immaculate I dare say it is a cap issue.

I've had a Packard Bell Pack-Mate III for months now, and I have upgraded it over time.

It has a 12hz 286 and originally came with 2mb of ram.

The BIOS says 1989 but the internal modem is from 1991, so I don't know when the machine was truly made, as sometimes older BIOS' are used.

I do need to attach my printer to it, so I will be looking at the back panel again, where it has a sticker with serial numbers and other things.

I don't know if there's a date on it or not, but I will take a look.

Does anyone know how to date a PB machine with stuff that could potentially be found on such a sticker?
]]>PCs and ClonesScanDiskhttp://www.vcfed.org/forum/showthread.php?59156-A-way-of-dating-packard-bell-computersNeed help with dead motherboard ibm 5160http://www.vcfed.org/forum/showthread.php?59149-Need-help-with-dead-motherboard-ibm-5160&goto=newpost
Sat, 12 Aug 2017 01:10:41 GMT(I'm very new to all this just trying to learn)

the PSU has correct voltages under load with everything removed. I reseated all the ram and replaced the first two banks with this ram http://www.jameco.com/z/41256-120-Ma...0aAlpvEALw_wcB after the reseat didn't work. I am not getting any life short of the PSU fan spinning I have left it on for 20min, no beeps. I found this sight http://www.mtmscientific.com/pc-retro.html and ordered the PC-RETRO OPTIONS: IC ADAPTER with DIAGNOSTIC ROM, but I dont think I can use it since it's only one chip not the two that the xt takes. any advice would be greatly appreciated.
]]>PCs and ClonesTkhtpchttp://www.vcfed.org/forum/showthread.php?59149-Need-help-with-dead-motherboard-ibm-5160Testing PS/2 hard drive that has an edge connectorhttp://www.vcfed.org/forum/showthread.php?59144-Testing-PS-2-hard-drive-that-has-an-edge-connector&goto=newpost
Fri, 11 Aug 2017 19:14:42 GMTI have an IBM WDL-320 hard drive here which is a 20MB ST-506 style drive from a PS/2 Model 30. It has a single card edge connector which combines...I have an IBM WDL-320 hard drive here which is a 20MB ST-506 style drive from a PS/2 Model 30. It has a single card edge connector which combines both power and signals, and I don't have anything that it can plug into.

Does anybody have a pinout handy before I go on another quest? I'd like to at least spin it up to see what it does. Testing it in a real PS/2 Model 30 would be best; I'm in the Seattle area if anybody can help.

This is actually exactly the same model that I used as a kid, except that one also had a hard drive. I'm therefore looking for a way to get a new hard drive for it. I think these models originally contained Miniscribe drives but they are ridiculously expensive online and probably very unreliable.

Someone on another forum mentioned to me that I might want to get an XT-IDE variant, which would allow me to connect Flash storage through IDE, which sounds to me like a perfect solution. I was able to find some information here but they seem to be out of stock. Would anyone here happen to know something similar that I could check out? Thanks!
]]>PCs and Clonesdadahttp://www.vcfed.org/forum/showthread.php?59115-Hard-drive-for-ancient-8088-pc2 questionhttp://www.vcfed.org/forum/showthread.php?59108-2-question&goto=newpost
Wed, 09 Aug 2017 08:48:12 GMThi
I have a 286 PC AT Clone (AMD N80L286-10 CPU if that matters) with a dying 122MB MFM drive that I'd like to replace (even though my games are all booters, it's the principle!)
What do you think my cheapest/most practical option would be: replace it with another MFM drive from eBay or doing a CF upgrade?
If I did the CF upgrade, what would be my best choice of components? I don't have an IDE controller card so I'd have to factor that in.

and second question

I just installed a recently-acquired copy of Wasteland on my CompuAdd 810 (a Turbo XT clone) and have been experiencing frequent system freezes while running the game. A cursory Google search shows that people have the same problem in DOSBOX depending on how many CPU cycles they have set to emulate, and additionally have been able to circumvent the problem by using a keyboard instead of a mouse.

This page details a fix using a hex editor and seems to indicate some timing logic is broken in the game whenever it has to re-draw the mouse pointer within the top 50 pixels of the screen:

So I thought I'd try running the game at 4.77 MHz instead of 10 MHz. Now I'm either avoiding the crash, or it's at least taking longer to get to it. So, is Wasteland actually a speed-sensitive game that has somehow escaped the speed-sensitive games lists, or do I have some other hardware/software issue at fault here?

thx all
]]>PCs and Clonesquanghieucihttp://www.vcfed.org/forum/showthread.php?59108-2-questionZenith ZFL-181-93 Video!http://www.vcfed.org/forum/showthread.php?59083-Zenith-ZFL-181-93-Video!&goto=newpost
Mon, 07 Aug 2017 20:55:27 GMTFor the second video on my new channel, I did an overview and review of my ZDS ZFL-181. I learned a lot of lessons from my first video, and I hope...For the second video on my new channel, I did an overview and review of my ZDS ZFL-181. I learned a lot of lessons from my first video, and I hope this one is better received :) Short, to the point, and much better audio.

I'd appreciate any feedback on the quality, audio, video, etc... I realized after I uploaded it that the MSD shot lists the 3.5" 720k Drives as 5.25 360k for some reason. Odd.
]]>PCs and Cloneszombienerdhttp://www.vcfed.org/forum/showthread.php?59083-Zenith-ZFL-181-93-Video!Looking for command line XMODEM prog for PC/MSDOShttp://www.vcfed.org/forum/showthread.php?59082-Looking-for-command-line-XMODEM-prog-for-PC-MSDOS&goto=newpost
Mon, 07 Aug 2017 20:48:22 GMTHello Folks,

I'm trying to find a simple command line driven X/Y/Zmodem prog for the PC but I'm drawing a blank.

I have found a number of drivers for BBS and some full featured comms programs but I would just like something that works along the lines of :-

I've been tinkering with an S-100 board that is an IBM PC Clone. After receiving some very valuable help from a friend, we've gotten to the point where there's output to the CGA monitor showing the BIOS messages. There's errors regarding the keyboard being dead and un-implemented interrupts. I'm posting the disassembly of the ROM on this forum and am looking for suggestions as to what may be causing these errors. What is the ROM doing to test for the keyboard? Attached is also a screenshot of what gets output to the screen, any feedback appreciated.